无法解析符号HttpEntity，HttpResponse

Question

我正在尝试使用this教程学习XML解析，但有些类没有导入。这是代码：

public String getXmlFromUrl(String url) {
    String xml = null;

    try {
        // defaultHttpClient
        DefaultHttpClient client = new DefaultHttpClient();
        HttpResponse resp = client.execute(uri);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        xml = EntityUtils.toString(httpEntity);

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    // return XML
    return xml;
}

这些类未导入：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.impl.client.DefaultHttpClient;

我的Gradle属性：

android {
    compileSdkVersion 23
    buildToolsVersion "21.1.2"

    defaultConfig {
        applicationId "com.example.rr.rio"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:23.0.0'
}

Answer 1

在pdk 23上弃用

HTTP client，而使用HttpURLConnection代替

或将其添加到您的gradle（不推荐）

android {
    useLibrary 'org.apache.http.legacy'
}

修改

public String getXmlFromUrl(String urlString) {
    String xml = null;

    URL url;
    HttpURLConnection urlConnection = null;

    try {
        url = new URL(urlString);

        urlConnection = (HttpURLConnection) url.openConnection();

        InputStream in = urlConnection.getInputStream();

        InputStreamReader isw = new InputStreamReader(in);

        BufferedReader br = new BufferedReader(isw);
        StringBuilder sb = new StringBuilder();
        String line;
        while ((line = br.readLine()) != null) {
            sb.append(line+"\n");
        }
        br.close();

        xml = sb.toString();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }


    // return XML
    return xml;
}

http://developer.android.com/about/versions/marshmallow/android-6.0-changes.html#behavior-apache-http-client

Answer 2

您可以在build.gradle（Module：app）中添加： sdk 23不支持HttpClient。您必须使用URLConnection或降级到sdk 22.

OR

如果您需要sdk 23，请将其添加到您的gradle：

android {
    useLibrary 'org.apache.http.legacy'
}

Answer 3

在API 23中删除了包org.apache.http。 如果您想将其用于学习，请使用较低的API，或查找替代方案。请看这个链接：HttpEntity is deprecated on Android now, what's the alternative?